Phytochrome modulation of blue light-induced chloroplast movements in arabidopsis

• Published in: Plant physiology (Bethesda) 2003-12, Vol.133 (4), p.1471-1479
• Main Authors: DeBlasio, S.L, Mullen, J.L, Luesse, D.R, Hangarter, R.P
• Format: Article
• Language: English
• Subjects: Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis - radiation effects; Arabidopsis thaliana; Biological and medical sciences; blue light; Cell motion; Cell physiology; Chloroplasts; Chloroplasts - physiology; Chloroplasts - radiation effects; chlorplast movement; far-red light; Ferns; Fluence; Focus Issue on Light Signaling; Fundamental and applied biological sciences. Psychology; Gene Deletion; gene overexpression; Hypocotyls; Irradiation; Kinetics; Leaves; Light; Molecular and cellular biology; Movement; Mutagenesis; Photoreceptors; phyA protein; phyB protein; phyD protein; phytochrome; Phytochrome - genetics; Phytochrome - metabolism; Plant cells; Plant Leaves - physiology; Plant Leaves - radiation effects; Plant physiology and development; Plants; red light; Transmittance; Vision, photoreception
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.029116

Photometric analysis of chloroplast movements in various phytochrome (phy) mutants of Arabidopsis showed that phyA, B, and D are not required for chloroplast movements because blue light (BL)-dependent chloroplast migration still occurs in these mutants. However, mutants lacking phyA or phyB showed an enhanced response at fluence rates of BL above 10 micromol m(-2) s(-1). Overexpression of phyA or phyB resulted in an enhancement of the low-light response. Analysis of chloroplast movements within the range of BL intensities in which the transition between the low- and high-light responses occur (1.5-15 micromol m(-2) s(-1)) revealed a transient increase in light transmittance through leaves, indicative of the high-light response, followed by a decrease in transmittance to a value below that measured before the BL treatment, indicative of the low-light response. A biphasic response was not observed for phyABD leaves exposed to the same fluence rate of BL, suggesting that phys play a role in modulating the transition between the low- and high-light chloroplast movement responses of Arabidopsis.